I use a XP computer for some 32bit-programs I bought for a lot of money years ago. I use Win7 64 bit for all the others. The problem is NOT to buy a cheap device, the probem is: I haven't 5000 Euro to buy a new 64bit or a fucking abo version, which needs money every month... Because I have this old XP, I use it for Visionaire. Why not? I never go online with XP no longer...
Edit: yes, a 32bit bus with Windows can only manage 2 GB per application, with some tricks up to 3 GB. Thats the limits of virtual memory adressing. Opening a browser in Win7 costs more than 6 GB memory after an hour, I think XP wouldn't handle it.

And of course, I use XP for all the old CDs with oldfashioned adventures, like MI, Simon, Tentacles, Myst, Syberia, Indiana Jones, Zork, and and and...